Caesar cipherCaesar cipher, is one of the simplest and most widely known encryption techniques.
The transformation can be represented by aligning two alphabets,
the cipher alphabet is the plain alphabet rotated left or right by some number of positions.
When encrypting, a person looks up each letter of the message in the 'plain'
line and writes down the corresponding letter in the 'cipher' line. Deciphering is done in reverse.
The encryption can also be represented using modular arithmetic
by first transforming the letters into numbers, according to the scheme, A = 0, B = 1,..., Z = 25.
Encryption of a letter x by a shift n can be described mathematically as
Plaintext: praemo

cipher variations:

qsbfnp

rtcgoq

sudhpr

tveiqs

uwfjrt

vxgksu

wyhltv

xzimuw

yajnvx

zbkowy

aclpxz

bdmqya

cenrzb

dfosac

egptbd

fhquce

girvdf

hjsweg

iktxfh

jluygi

kmvzhj

lnwaik

moxbjl

npyckm

oqzdln

Decryption is performed similarly,
(There are different definitions for the modulo operation.
In the above, the result is in the range 0...25. I.e., if x+n or x-n are not in the range 0...25,
we have to subtract or add 26.)
Read more ...Atbash CipherAtbash is an ancient encryption system created in the Middle East.
It was originally used in the Hebrew language.
The Atbash cipher is a simple substitution cipher that relies on
transposing all the letters in the alphabet such that the resulting alphabet is backwards.
The first letter is replaced with the last letter, the second with the second-last, and so on.
An example plaintext to ciphertext using Atbash:

Baconian CipherTo encode a message, each letter of the plaintext is replaced by a group of five of the letters 'A' or 'B'.
This replacement is done according to the alphabet of the Baconian cipher, shown below.

Affine CipherIn the affine cipher the letters of an alphabet of size m are first mapped to the integers
in the range 0..m - 1. It then uses modular arithmetic to transform the integer that each plaintext
letter corresponds to into another integer that correspond to a ciphertext letter.
The encryption function for a single letter is
where modulus m is the size of the alphabet and a and b are the key of the cipher.
The value a must be chosen such that a and m are coprime.Considering the specific case of encrypting messages in English (i.e. m = 26),
there are a total of 286 non-trivial affine ciphers, not counting the 26 trivial Caesar ciphers.
This number comes from the fact there are 12 numbers that are coprime with 26 that are less than 26
(these are the possible values of a). Each value of a can have 26 different addition shifts (the b value)
; therefore, there are 12*26 or 312 possible keys.Plaintext: praemo

cipher variations:

qsbfnp

uabnlr

yibvjt

cqbdhv

gyblfx

kgbtdz

swbjzd

webrxf

ambzvh

eubhtj

icbprl

mkbxpn

rtcgoq

vbcoms

zjcwku

drceiw

hzcmgy

lhcuea

txckae

xfcsyg

bncawi

fvciuk

jdcqsm

nlcyqo

sudhpr

wcdpnt

akdxlv

esdfjx

iadnhz

midvfb

uydlbf

ygdtzh

codbxj

gwdjvl

kedrtn

omdzrp

tveiqs

xdeqou

bleymw

ftegky

jbeoia

njewgc

vzemcg

zheuai

dpecyk

hxekwm

lfesuo

pneasq

uwfjrt

yefrpv

cmfznx

gufhlz

kcfpjb

okfxhd

wafndh

aifvbj

eqfdzl

iyflxn

mgftvp

qofbtr

vxgksu

zfgsqw

dngaoy

hvgima

ldgqkc

plgyie

xbgoei

bjgwck

frgeam

jzgmyo

nhguwq

rpgcus

wyhltv

aghtrx

eohbpz

iwhjnb

mehrld

qmhzjf

ychpfj

ckhxdl

gshfbn

kahnzp

oihvxr

sqhdvt

xzimuw

bhiusy

fpicqa

jxikoc

nfisme

rniakg

zdiqgk

dliyem

htigco

lbioaq

pjiwys

triewu

yajnvx

cijvtz

gqjdrb

kyjlpd

ogjtnf

sojblh

aejrhl

emjzfn

iujhdp

mcjpbr

qkjxzt

usjfxv

zbkowy

djkwua

hrkesc

lzkmqe

phkuog

tpkcmi

bfksim

fnkago

jvkieq

ndkqcs

rlkyau

vtkgyw

aclpxz

eklxvb

islftd

malnrf

qilvph

uqldnj

cgltjn

golbhp

kwljfr

oelrdt

smlzbv

wulhzx

bdmqya

flmywc

jtmgue

nbmosg

rjmwqi

vrmeok

dhmuko

hpmciq

lxmkgs

pfmseu

tnmacw

xvmiay

cenrzb

gmnzxd

kunhvf

ocnpth

sknxrj

wsnfpl

einvlp

iqndjr

mynlht

qgntfv

uonbdx

ywnjbz

dfosac

hnoaye

lvoiwg

pdoqui

tloysk

xtogqm

fjowmq

jroeks

nzomiu

rhougw

vpocey

zxokca

egptbd

iopbzf

mwpjxh

qeprvj

umpztl

yuphrn

gkpxnr

kspflt

oapnjv

sipvhx

wqpdfz

aypldb

fhquce

jpqcag

nxqkyi

rfqswk

vnqaum

zvqiso

hlqyos

ltqgmu

pbqokw

tjqwiy

xrqega

bzqmec

girvdf

kqrdbh

oyrlzj

sgrtxl

worbvn

awrjtp

imrzpt

murhnv

qcrplx

ukrxjz

ysrfhb

carnfd

hjsweg

lrseci

pzsmak

thsuym

xpscwo

bxskuq

jnsaqu

nvsiow

rdsqmy

vlsyka

ztsgic

dbsoge

iktxfh

mstfdj

qatnbl

uitvzn

yqtdxp

cytlvr

kotbrv

owtjpx

setrnz

wmtzlb

authjd

ectphf

jluygi

ntugek

rbuocm

vjuwao

zrueyq

dzumws

lpucsw

pxukqy

tfusoa

xnuamc

bvuike

fduqig

kmvzhj

ouvhfl

scvpdn

wkvxbp

asvfzr

eavnxt

mqvdtx

qyvlrz

ugvtpb

yovbnd

cwvjlf

gevrjh

lnwaik

pvwigm

tdwqeo

xlwycq

btwgas

fbwoyu

nrweuy

rzwmsa

vhwuqc

zpwcoe

dxwkmg

hfwski

moxbjl

qwxjhn

uexrfp

ymxzdr

cuxhbt

gcxpzv

osxfvz

saxntb

wixvrd

aqxdpf

eyxlnh

igxtlj

npyckm

rxykio

vfysgq

znyaes

dvyicu

hdyqaw

ptygwa

tbyouc

xjywse

bryeqg

fzymoi

jhyumk

oqzdln

syzljp

wgzthr

aozbft

ewzjdv

iezrbx

quzhxb

uczpvd

ykzxtf

cszfrh

gaznpj

kizvnl

praemo

tzamkq

xhauis

bpacgu

fxakew

jfascy

rvaiyc

vdaqwe

zlayug

dtagsi

hbaoqk

ljawom

The decryption function iswhere a - 1 is the modular multiplicative inverse of a modulo m. I.e., it satisfies the equationThe multiplicative inverse of a only exists if a and m are coprime.
Hence without the restriction on a decryption might not be possible.
It can be shown as follows that decryption function is the inverse of the encryption function,Read more ...

ROT13 CipherApplying ROT13 to a piece of text merely requires examining its alphabetic
characters and replacing each one by the letter 13 places further along in the alphabet,
wrapping back to the beginning if necessary. A becomes N, B becomes O, and so on up to M,
which becomes Z, then the sequence continues at the beginning of the alphabet: N becomes A,
O becomes B, and so on to Z, which becomes M. Only those letters which occur in the English
alphabet are affected; numbers, symbols, whitespace, and all other characters are left unchanged.
Because there are 26 letters in the English alphabet and 26 = 2 * 13, the ROT13 function is its own inverse:

Polybius SquareA Polybius Square is a table that allows someone to translate letters into numbers.
To give a small level of encryption, this table can be randomized and shared with the recipient.
In order to fit the 26 letters of the alphabet into the 25 spots created by the table, the letters
i and j are usually combined.

1

2

3

4

5

1

A

B

C

D

E

2

F

G

H

I/J

K

3

L

M

N

O

P

4

Q

R

S

T

U

5

V

W

X

Y

Z

Basic Form:

Plain:

praemo

Cipher:

532411512343

Extended Methods:Method #1

Plaintext: praemo

method variations:

uwfkrt

zblpwy

egqubd

kmvzgi

Method #2Bifid cipherThe message is converted to its coordinates in the usual manner, but they are written vertically beneath:

p r a e m o
5 2 1 5 2 4
3 4 1 1 3 3

They are then read out in rows:
521524341133Then divided up into pairs again, and the pairs turned back into letters using the square:

Permutation CipherIn classical cryptography, a permutation cipher is a transposition cipher in which the key is a permutation.
To apply a cipher, a random permutation of size E is generated (the larger the value of E the more secure the cipher).
The plaintext is then broken into segments of size E and the letters within that segment are permuted according to
this key.
In theory, any transposition cipher can be viewed as a permutation cipher where E is equal to the
length of the plaintext; this is too cumbersome a generalisation to use in actual practice, however.
The idea behind a permutation cipher is to keep the plaintext characters unchanged,
butalter their positions by rearrangement using a permutation
This cipher is defined as:Let m be a positive integer, and K consist of all permutations of {1,...,m}For a key (permutation) , define:
The encryption function The decryption function A small example, assuming m = 6, and the key is the permutation
:The first row is the value of i,
and the second row is the corresponding value of (i)The inverse permutation, is constructed by interchanging the two rows,
andrearranging the columns so that the first row is in increasing order, Therefore, is:
Total variation formula: e = 2,718281828 , n - plaintext length